Damper assemblies in ductwork include a movable damper capable of occluding the interior of the duct, a control shaft attached to the damper and extending through an opening in the duct to the exterior, a handle fitted onto the control shaft, and means for securing the handle onto the control shaft such as a nut.
Damper assemblies contained within short sections of a duct are commonly available in complete units, having been assembled at the factory. The control shafts on the prefabricated assemblies extend out from the duct only a short distance. When the damper assembly is wrapped with insulation, along with the rest of the ductwork, the control shaft does not extend out past the insulation, making the installation of the handle onto the control shaft difficult. The handle could be installed onto the short control shaft by compressing the insulation around the control shaft. This diminishes the effectiveness of the insulation however, and creates difficulty when trying to rotate the handle. Attempts to weld an extension onto the control shaft have proven to be unsatisfactory because of the expense involved and the probability of melting the surrounding insulation.
Accordingly, it is an object of the present invention to provide an apparatus that will effectively extend the control shaft of a damper assembly without difficulty.